International Industrial Ecology Day 2021

Buildings are material- and energy-intensive, being responsible for a large share of environmental impacts. Prefabricated buildings are usually based on lightweight construction, using fewer materials with fewer impacts. However, reduced embodied impacts of lightweight construction may be balanced by increased energy consumption, so prefabricated buildings must be assessed in different locations and with different insulations. A life cycle assessment (LCA) of a prefabricated house was performed to analyze the influence of the heating ventilation and air-conditioned (HVAC) system, different insulation levels, and house locations (assessing different climates, transport, and electricity mixes). The life-cycle model includes material, transport to site, plant production, transport to site, onsite assemblage, and use phase. Impacts were calculated for eight categories: abiotic depletion, abiotic depletion fossil fuels, global warming, ozone layer depletion, photochemical oxidation, acidification, and eutrophication (using the CML method); and Non-renewable energy (using the Cumulative Energy Demand method). A building information model (BIM) was used to build the life-cycle inventory and perform the energy simulation. Results show that operational impacts are the most critical (40-90%), and embodied impacts can be significant in moderate or warm climates (up to 60%). Local climate and the electricity mix influence impacts, and transport and HVAC systems have a minor influence. To reduce prefabricated building impacts, embodied and operation phases have to be optimized. Prefabricated buildings should use weather-adjusted insulation and a preferable electricity mix (reducing operational impacts) and avoid impact-intensive materials and processes (reducing embodied impacts). The BIM-LCA approach can streamline building assessment and support eco-design.